scholarly journals The BioChemical Clogging of Landfill Leachate Collection System: Based on Laboratory Studies

2020 ◽  
Vol 17 (7) ◽  
pp. 2299 ◽  
Author(s):  
Yili Liu ◽  
Jianguo Liu
Keyword(s):  
Volatile Fatty Acids ◽  
Dominant Role ◽  
Experimental Period ◽  
Laboratory Studies ◽  
Improved Method ◽  
Collection System ◽  
Leachate Collection ◽  
Operational Problem ◽  
Drainage Layers ◽  
Nonwoven Geotextile

Leachate collection system (LCS) clogging is a common operational problem in municipal solid waste (MSW) landfills in China, which can result in high leachate levels that threaten the safety of landfill operations and subsequently increase the leachate leakage risk. In our previous research, a filtration test was conducted and the physical clogging effect was evaluated. To fully analyze the LCS failure, in this study, a set of column experiments were carried out to investigate the biochemical clogging development and mechanisms. Results showed that the biofilm and deposited CaCO3 composed the primary clogging materials. During the experimental period, the hydraulic conductivities in simulated gravel and nonwoven geotextile drainage layers were observed (91.7% and five orders of magnitude reduction), and decreased to 10−4 and 10−8 m s−1, respectively. Therefore, the significance of the geotextile layer in LCS designing needs to be reconsidered. The biochemical clogging was positively correlated with volatile fatty acids (VFAs), and Ca2+ loading and the Ca2+ played the dominant role. Meanwhile, an improved method for analyzing biochemical clogging development was proposed.

scholarly journals 79 Effect of source and dietary concentration of trace minerals on serum mineral status, ruminal pH, and ruminal volatile fatty acids in lactating Holstein dairy cows

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 71-71
Author(s):  
Nicole T Briggs ◽  
Bayissa Hatew ◽  
Michael A Steele
Keyword(s):  
Volatile Fatty Acids ◽  
Rumen Fluid ◽  
Latin Square ◽  
Experimental Period ◽  
Rumen Fermentation ◽  
Trace Minerals ◽  
Trace Mineral ◽  
Mineral Status ◽  
Ruminal Ph ◽  
Dietary Concentration

Abstract Inorganic sources of trace minerals are commonly supplemented in dairy cow diets; however, there has been an increase in the supplementation of minerals complexed with organic compounds. These organic trace minerals are thought to have greater bioavailability which may enhance rumen fermentation and absorption. The objective of this study was to assess the effects of dietary concentration and source of supplemental trace minerals on serum trace mineral status and rumen fermentation. Six lactating Holstein cows were used in a 6 x 6 Latin square design with a 23-day adaptation and 5-day experimental period. Cows were fed the same basal diet daily except for the difference in source [organic (ORG) versus inorganic (INO)] and concentration (50%, 100%, and 200% based on NRC recommendations) of trace mineral supplemented. During the experimental period feed intake and blood were collected daily. Rumen fluid was collected on the final two days of the experimental period. Data was analyzed with PROC MIXED in SAS 9.4. Dry matter intake (18.1 ± 0.70 kg), serum mineral concentrations (Cu, Mn, Se, and Zn), and rumen pH (6.5 ± 0.64) did not differ among the treatments. However, serum concentration of Co was higher in 200% ORG compared to 50% and 100% INO and 50% ORG. Ruminal concentration of acetate was higher in 50% and 100% ORG compared to 200% ORG. Butyrate ruminal concentration was higher at 50% ORG compared to 200% ORG. Ruminal propionate concentration was higher in 50% INO and 50% ORG compared to 100% INO and 200% ORG. These findings demonstrate serum trace mineral status and ruminal pH are not tightly controlled by the source of trace minerals when supplemented at 50%, 100% and 200% of the NRC recommendations, however rumen fermentation may be affected by the dietary concentration of trace minerals in the diet.

A practical technique for estimating service life of MSW leachate collection systems

2013 ◽  
Vol 50 (2) ◽  
pp. 165-178 ◽  
Author(s):  
R. Kerry Rowe ◽  
Yan Yu
Keyword(s):  
Numerical Model ◽  
Service Life ◽  
Field Data ◽  
Oxygen Demand ◽  
Collection System ◽  
Leachate Collection ◽  
Design Charts ◽  
Leachate Characteristics ◽  
Practical Model ◽  
Measured Field

The leachate characteristics and clogging of the leachate collection system at the Keele Valley Landfill is examined using the numerical model “BioClog”. The calculated effluent leachate concentrations (e.g., the chemical oxygen demand and calcium concentrations) and calculated calcium fraction in the clog material are in encouraging agreement with measured field data. A new practical model is developed and calibrated against the data from the sophisticated numerical model to estimate the service life of leachate collection systems in typical municipal solid waste (MSW) landfills. The procedures for using the new practical model are provided and illustrated by examples. Design charts are presented that may aid the design of leachate collection systems for typical MSW landfills.

Evaluation of ketogenic vs. glucogenic substrates as energy sources in starter diets for Holstein dairy calves

2014 ◽  
Vol 94 (4) ◽  
pp. 717-723 ◽  
Author(s):  
H. Beiranvand ◽  
M. Khorvash ◽  
G. R. Ghorbani ◽  
A. Homayouni ◽  
L. Bachmann ◽  
...  
Keyword(s):  
Volatile Fatty Acids ◽  
Average Daily Gain ◽  
Experimental Period ◽  
Dairy Calves ◽  
Energy Sources ◽  
Sodium Propionate ◽  
Waste Milk ◽  
Weaning Age ◽  
Calf Performance ◽  
Holstein Calves

Beiranvand, H., Khorvash, M., Ghorbani, G. R., Homayouni, A., Bachmann, L. and Kargar, S. 2014. Evaluation of ketogenic vs. glucogenic substrates as energy sources in starter diets for Holstein dairy calves. Can. J. Anim. Sci. 94: 717–723. The objective of this study was to investigate the influence of the inclusion of granular sugar and sodium propionate as ketogenic and glucogenic substrates, respectively, in calf starter diets on the performance, weaning age, rumen fermentation characteristics and plasma β-hydroxybutyrate (βHBA). Twenty-one newborn male Holstein calves were housed in individual pens until 10 wk of age, receiving starter ad libitum, fresh water free choice, and fed four liters of pasteurized waste milk daily until weaning. Calves were randomly assigned to one of the following treatments: (1) no supplemental additive (Control); (2) granular sugar (5% of dietary DM; Sugar); and (3) sodium propionate (5% of dietary DM; Propionate). Overall, no differences were observed among treatments for starter intake, average daily gain, feed efficiency, day of weaning, body weight at weaning and at the end of the study. Body measurements including body length, hip height, hip width, and heart girth were remained unchanged among treatments. Ruminal fluid pH (5.36 to 5.58) and concentrations of total volatile fatty acids (93.1 to 101.6 mM), acetate (43.6 to 53.1 mM), propionate (30.5 to 35.1 mM), and ratio of acetate to propionate (1.42 to 1.89) were not affected by treatments over the experimental period. However, the concentration of butyrate was greater at 35 and 70 d of age in calves receiving Sugar compared with calves receiving Propionate, but not compared with the Control. Greater blood βHBA at 45, 60 and 70 d of age was noticed in calves fed Sugar compared with those fed Control and Propionate. In conclusion, according to the concentrations of supplemental ketogenic and glucogenic substrates used in the current experiment, sugar and sodium propionate in starter diets did not improve calf performance.

Clogging of unsaturated gravel permeated with landfill leachate

2008 ◽  
Vol 45 (8) ◽  
pp. 1045-1063 ◽  
Author(s):  
Reagan McIsaac ◽  
R. Kerry Rowe
Keyword(s):  
Experimental Investigation ◽  
Landfill Leachate ◽  
Retention Time ◽  
Total Surface Area ◽  
Collection System ◽  
Waste Landfill ◽  
Leachate Collection ◽  
Flow Pathways ◽  
Inorganic Constituents ◽  
Drainable Porosity

The results of an experimental investigation into the clogging of unsaturated, uniformly graded 50 mm gravel permeated with municipal solid waste landfill leachate are reported. The flow of leachate within the unsaturated gravel was heterogeneous and occurred in free-draining flow pathways. The leachate experienced reductions in the concentrations of both the organic and inorganic constituents after passing through the unsaturated gravel although there was very little clogging within the unsaturated gravel. The average drainable porosity was reduced by 8% after 8 years permeation. The biofilm was limited to areas on the gravel where leachate could be retained; predominantly on top of lateral gravel surfaces and near particle-to-particle contacts. As a result, only a small fraction of the total surface area of the unsaturated gravel was covered with biofilm. The short leachate retention time and the sporadic distribution of biofilm limited the degree of contact between the bacteria and the leachate and hence limited biologically induced clogging within the unsaturated gravel. The data suggest that leachate collection systems should be designed and operated such that the drainage material of the leachate collection system remains unsaturated for as long as possible.

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